Powder feeders and metering devices are used to measure the amount of powder or other flowable material being processed or applied to a target or substrate. The rate of flow can be affected by such variables as humidity, particle size, particle shape, density, material cohesiveness, and chemical composition. These alone, or in combination at times, render many existing powder feeders useless or troublesome.
Metering and aerating of fine particles for application on a substrate or target has been developed for easily flowable materials. But, application of materials that do not flow easily cause problems in traditional devices. Such materials are difficult to measure and meter in an applicator. These materials may form large or hard agglomerates naturally or when exposed to normally benign environmental conditions, such as slight humidity. Examples of such materials may be sugars or salts. Aeration of these materials can be difficult and tribo-charging may also occur during an application process causing the material to stick together (form agglomerates) or stick to components of the application device.